Represents the assumed rate of return for each class of pension and other post retirement benefit plan assets

No definition available.

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- Definition

Defined Benefit Plan, Decrease of Liability As A Result of Change in Discount Rate

+ References

No definition available.

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- Definition

Defined Benefit Plan, Health Care Trend Rate

+ References

No definition available.

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- Definition

Defined Benefit Plan, Increase of Liability As A Result of Change in Discount Rate

+ References

No definition available.

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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- Definition

Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

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- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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EMPLOYEE BENEFITS - Pension Plan Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Expected long-term rate of return	7.94%	7.00%
Pension and SERP
Defined Contribution Plan Disclosure [Line Items]
Decrease in liability as a result of a change in discount rate		$ 1,480.0
Increase of liability as a result of change in discount rate	$ 98.9
Expected long-term rate of return	8.25%	8.25%	8.25%
Employer Contributions	$ 5.0	$ 80.0
Estimated future employer contributions in next fiscal year	5.0
Pension and SERP \| CL&P
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	0.0	0.0
Pension and SERP \| PSNH
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	0.0	0.0
PBOP
Defined Contribution Plan Disclosure [Line Items]
Decrease in liability as a result of a change in discount rate	17.0	$ 180.1
Increase of liability as a result of change in discount rate	$ 12.0
Expected long-term rate of return	8.25%	8.25%	8.25%
Employer Contributions	$ 1.9	$ 3.1
Estimated future employer contributions in next fiscal year	$ 2.4
PBOP \| Aquarion
Defined Contribution Plan Disclosure [Line Items]
Expected long-term rate of return	7.00%	7.00%
PBOP \| CL&P
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	$ 0.0	$ 0.0
PBOP \| PSNH
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	$ 0.0	$ 0.0
Pre-65 Plan \| PBOP
Defined Contribution Plan Disclosure [Line Items]
Health care trend rate	6.75%
Ultimate rate	5.00%
Pre-65 Plan \| Minimum \| PBOP \| Aquarion
Defined Contribution Plan Disclosure [Line Items]
Health care trend rate	3.50%	3.50%
Pre-65 Plan \| Maximum \| PBOP \| Aquarion
Defined Contribution Plan Disclosure [Line Items]
Health care trend rate	7.00%	6.50%
Post-65 Plan \| PBOP
Defined Contribution Plan Disclosure [Line Items]
Ultimate rate	3.50%
Eversource Service Pension and PBOP Plans
Defined Contribution Plan Disclosure [Line Items]
Assumed rate of return	8.25%
Aquarion Plans
Defined Contribution Plan Disclosure [Line Items]
Assumed rate of return	7.00%